1. Field of The Invention
The present invention relates to a socket for electrical parts for detachably accommodating an electrical part such as a semiconductor device (called as xe2x80x9cIC packagexe2x80x9d hereinafter), and more particularly, to a socket for electrical parts having a structure for effectively acting an urging force of an urging member for urging an open/close member in a direction pressing it against an IC package body.
2. Related Art
As a xe2x80x9csocket for electrical partsxe2x80x9d of this kind, there is provided an IC socket for detachably accommodating an IC package as xe2x80x9celectrical partxe2x80x9d, and one example having such structure is shown in FIGS. 6 to 8.
FIG. 6 is a plan view of such IC socket including an upper half portion in which an open/close member is opened and a lower half portion in which the open/close member is closed. FIG. 7 is a sectional view taken along the line VIIxe2x80x94VII in FIG. 6, showing the closed state of the open/close member, and FIG. 8 is also a sectional view taken along the line VIIIxe2x80x94VIII in FIG. 6 showing the opened state of the open/close member.
In a case where a performance test of an IC package is carried out by using this IC socket, as shown in FIGS. 6 to 8, an open/close member 41 having a heat sink 40 is mounted to a socket body 42, to be rotatable (pivotal) about a rotational shaft 43, so as to press downward the IC package body and to remove heat generated in the IC package. The IC package 50 is then rested on a mount surface portion 45 of an IC socket 44, and thereafter, the heat sink 40 is disposed so as to abut against an upper surface of the IC package 50 to thereby press the body portion of the IC package 50 with a predetermined pressure and carry out the heat radiation during.this process.
A torsion coil spring 46 as a member for urging the open/close member 41 in a direction of closing the same is arranged between the socket body 42 and the open/close member 41 having the heat sink 40. More specifically, the torsion coil spring 46 has a rod-like portion 46a, and a front end portion of the rod-like portion 46a is engaged with an end portion of the open/close member 41 positioned apart from the rotational shaft 43 of the open/close member 41, a coil (coiled) portion 46b of the torsion coil spring 46 is wound up around the rotational shaft 43, and the end portion 46c of the coil portion 46b is engaged with the rotational shaft 43 so as not to be rotated, thereby urging the open/close member 41 in its closing direction.
Further, in a case where the open/close member 41 is opened for mounting the IC package 50, the end side of the open/close member 41 is opened against the urging force of the torsion coil spring 46 about the rotational shafts 43 as shown in FIG. 8.
In the IC socket 44 of the structure mentioned above, the rod-like portion 46a of the torsion coil spring 46 is rotated by the same angle xcex81 (displacement amount) of the open/close member 41 according to the opening movement of the open/close member, as shown in FIG. 7.
On the other hand, in order to ensure a contact pressure sufficient for contacting the heat sink 40 against the IC package body, it will be done to increase the winding number of the coil portion 46b of the torsion coil spring 46 or to make large the coil portion in average diameter.
However, increasing of the urging force of the torsion coil spring 46 by increasing the winding number or making large the average diameter of the coil windings results in increasing of a force required for opening the open/close member 41 and, hence, increasing of a space for arranging the torsion coil spring 46, and moreover, because of the rotation angle xcex81 (displacement) of the rod-like portion 46a of the torsion coil spring 46, the operational durability of the torsion coil spring 46 will be made worse.
An object of the present invention is to substantially eliminate defect or drawbacks encountered in the related art mentioned above and to provide a socket for electrical parts capable of, while maintaining a predetermined contact pressure contacting an open/close member against a body of an electrical part such as IC package, reducing a force for opening the open/close member by reducing an urging force of an urging member that generates such contact pressure, making compact the entire structure of the socket and improving an operational durability thereof.
This and other objects can be achieved according to the present invention by providing, in one aspect, a socket for an electrical part which comprises an open/close member mounted, to be rotatable about a rotational shaft, to a socket body in which an electrical part is accommodated, an urging member for urging the open/close member in a closed direction thereof, and an operation member vertically movable with respect to the socket body and in which the open/close member is opened against the urging force of the urging member by depressing the operation member, wherein one end portion of the urging member is engaged with a portion of the open/close member apart from a rotation center thereof and another end portion of the urging member is engaged with the operation member.
According to this aspect of the invention, in accordance with the depressing motion of the operation member, the other end portion of the urging member is also lowered and escapes. Moreover, even if another urging member having an urging force weak in amount corresponding to the escaping amount be used, while a pressure contacting the heat sink to the IC package is maintained at a predetermined value, the urging force of the urging member generating such contacting pressure can be made weak to thereby reduce the opening force to the open/close member. Furthermore, the entire structure of the socket for electrical parts can be made compact in size. The operational performance and durability thereof can be also improved.
According to the preferred embodiment of the present invention, the urging member is a torsion coil spring having a coil portion, the one end portion extending from the coil portion and being engaged with that portion of the open/close member, and the another end portion extending from the coil portion, the coil portion being wound up around the rotational shaft.
The operation member is formed with an engagement portion with which the another end portion of the urging member is engaged and an escape portion, in which the another end portion is rotated according to lowering motion of the operation member, is formed to the operation member outside the engagement portion.
An auxiliary urging member for urging upward the operation member is disposed between the socket body and the operation member.
The open/close member is provided with a heat sink radiating a heat through contact to the electrical part. The heat sink is provided with an urging force adjusting device for urging the heat sink in a direction contacting to the electrical part. The urging force adjusting device includes a plurality of urging force adjusting members which are disposed apart from each other.
According to the structures of the above preferred embodiment, there acts a force for rotating the open/close member in its closing direction by means of the torsion coil spring with the contact portion between the inside portion of the coil portion of the torsion coil spring and the rotational shaft being fulcrum, and hence, the pressure for pressing the heat sink against the electrical part can be increased.
Furthermore, according to the formation of the escape portion, the other end portion of the urging member is guided to this escape portion by rotating at a predetermined degree of angles, so that the open/close member can be fully opened with a reduced rotation angle of the urging member. Thus, substantially the same urging force as that in the structure in which the other end is fixed can be achieved by using the urging member having a compact size and structure.
Still furthermore, the provision of the auxiliary urging member can apply an additional urging force to the urging member directly urging the open/close member in its closing direction. Accordingly, the pressing force for contacting the open/close member against the electrical part of such as IC package can be adjusted to thereby improve the heat radiation performance of the electrical part.
In addition, the location of the heat sink to the portion contacting the upper surface of the electrical part can avoid abnormal increasing of temperature of the electrical part and the performance test thereof can be precisely carried out. The location of the urging force adjusting member to the heat sink can achieve the adjustment of the contact pressure pressing the heat sink to the electrical part such as IC package, and hence, the heat radiation of the electrical part can be improved.
Further, the location of the plural urging force adjusting members can also achieve the adjustment of the contact pressure of the heat sink, and accordingly, the heat sink can be surely closely contacted to the IC package even having a relatively large size, thus improving the heat radiation of the IC package.
The above mentioned objects of the present invention will be also achieved by providing a socket for an electrical part of the another aspect having more specific structure. That is, there is provided, in a modified aspect, a socket for an electrical part comprising:
a socket body to which an electrical part is accommodated;
an open/close member mounted to the socket body to be rotatable about a rotational shaft;
an urging member for urging the open/close member in a direction of closing the open/close member; and
an operation member provided for the socket body to be vertically movable with respect to the socket body, the urging member having one end portion engaged with a portion of the open/close member apart from a rotation center thereof and another end portion engaged with the operation member.